1. Field of the Invention
The present invention relates to a chemically amplified resist composition and, more particularly, to a photosensitive polymer whose backbone has a cyclic structure, and to a resist composition containing the photosensitive polymer for an ArF excimer laser.
2. Description of the Related Art
As semiconductor devices become highly integrated and complicated to fabricate, fine pattern formation is required. Further, as the capacity of a semiconductor device increases to exceed 1 giga bit, a pattern size having a design rule of less than 0.2 .mu.m is required. Accordingly, there are limitations in using a conventional resist material with a KrF excimer laser (248 nm). Thus, a new resist material capable of being developed using an ArF excimer laser (193 nm) has been developed in a lithography process.
The conventional resist material used in the lithography process using the ArF excimer laser has several problems in commercial use, when compared to the conventional resist materials using other lasers, such as the KrF excimer laser. The most typical problems include transmittance of a polymer, and resistance to dry etching. As the widely known ArF resist materials, (meth)acrylate polymers are generally used. In particular, the most typical resist material is poly(methyl methacrylate-tert-butyl methacrylate-methacrylic acid) terpolymer system manufactured by IBM, Inc. However, such polymers have very weak resistance to dry etching. Accordingly, to increase the resistance to dry etching, a polymer having a backbone composed of an alicyclic compound such as an isobornyl group, an adamantyl group or a tricyclodecanyl group, is used. However, the resulting resist still exhibits weak resistance to dry etching.